Throttle Socket watcher RTT notifications from QUIC

net/quic/chromium/quic_connection_logger.cc

Index: net/quic/chromium/quic_connection_logger.cc
diff --git a/net/quic/chromium/quic_connection_logger.cc b/net/quic/chromium/quic_connection_logger.cc
index 1e451e366e37ac3677f6d1e7e0503123114987e9..27128a3a0a01edb309274fa42411fa135267c501 100644
--- a/net/quic/chromium/quic_connection_logger.cc
+++ b/net/quic/chromium/quic_connection_logger.cc
@@ -686,7 +686,8 @@ void QuicConnectionLogger::OnRttChanged(QuicTime::Delta rtt) const {
     return;
 
   int64_t microseconds = rtt.ToMicroseconds();
-  if (microseconds != 0) {
+  if (microseconds != 0 &&
+      socket_performance_watcher_->ShouldNotifyUpdatedRTT()) {
     socket_performance_watcher_->OnUpdatedRTTAvailable(

[Ryan Hamilton, 2017/02/15 23:08:16]

I guess this is fine, but any reason not to make the impl of
OnUpdatedRTTAvailable do:

OnUpdatedRTTAvailable() {
 if (!ShouldNotifyUpdatedRTT())
   return;
  ...
}

And leave callers unchanged?

[tbansal1, 2017/02/15 23:16:12]

The reason is that we do not want TCP Socket Posix to make a syscall unless the
Socket Watcher is interested in receiving a reading. So, the socket first checks
if the Watcher is interested in the reading before making any effort to generate
one.

         base::TimeDelta::FromMicroseconds(rtt.ToMicroseconds()));
   }